Heating problem

[RustyRick]

I watched my brother this week shoot his 56-06 X-Bolt. 16 X scope at 100 yrds hand loads. He's been some frustrated with groups in the 2 to 2.5" size. He would get shot one and 2 within the inch. Then they would spread.

So I guessed it's a heating / barrel expansion situation.

So the last rounds he would shoot 1 round, and go shoot his 22. Come back round 2, go shoot the 22, cool of his barrel, come back round 3, to 5.

Sure enough shrunk his 5 shot group to just over the inch.

What beside heating expansion might it be?

 

[Engineering101]

Could be a combination of things where letting a barrel get hot makes it worse. For example if the barrel is not floating when it gets hot it pushes on the stock which is not good for consistent bullet placement. If the barrel fully floats that at least won't happen. Most guns shoot better groups if you let the barrel cool between shots so this is not unusual but in this case it seems to be a bit more pronounced. If a gun is put together right it can shoot good groups even if the barrel warms up but that takes some design and manufacturing know how. Good luck.

 

[shortgrass]

Poor bedding, crappy barrel , you name it with a factory rifle, and I don't care who's name is on it.

 

[RustyRick]

i should said we ran a $5 bill through it and that seemed OK. Mind you our moneys getting pretty thin these days.

 

[engineer40]

Even free floated barrels will have POI shifts when they get heated. It has to do with metallurgy; how the barrel was stressed when being manufactured.

I agree with shortgrass, doesn't seem to matter who's name is on it.

I have some barrels that don't walk much when heated. I have some that I would be embarrassed to show a target shot with a hot barrel; meaning some barrels are much worse than others.

Everyone struggles with this. A lot of guys on here will say that it's only the first shot that counts. Which is true. But heated barrels are still a pain when doing load development.